1. Field
The present disclosure relates to an apparatus and a method for transmitting a signal using a power amplifier in a wireless communication system.
2. Description of Related Art
Recently, a distributed base station architecture is studied and developed in a wireless communication system. The distributed base station architecture is configured by separating a remote radio units (RRUs) (or radio frequency (RF) transceivers) from a base station and relocating them close to antennas so that a plurality of antennas operates with a minimum transmission power loss. That is, in the distributed base station architecture, a plurality of RRUs is distributed within one cell, wherein the plurality of the RRUs is installed at a considerable distance from a main unit of the base station and is connected by optic cables. The RRU includes a transceiver, a power amplifier, and a front-end unit.
A digital pre-distorter (DPD) is used to improve nonlinearity of the power amplifier in the wireless communication system. In other words, in the wireless communication system, a signal is distorted according to characteristics of the power amplifier using the DPD, and then the nonlinearity of the power amplifier is improved by using the distorted signal as an input of the power amplifier.
However, if a connection state between an output of the RRU and the antenna is not good, a high return loss occurs. Due to such a high return loss, the DPD may not generate the distorted signal which accurately reflects the characteristic of the power amplifier.